Wheel balancing devices are used for determining the positions and sizes of balancing weights, which are to be attached to a wheel in order to correct imbalances.
If the wheel to be balanced is a spoked wheel, it is desirable to attach the balancing weights at the positions of the spokes, in particular, behind the spokes of the wheel, in the circumferential direction of the wheel. To that end, the positions of the spokes must be known to the wheel balancing device. In order to make the positions of the spokes known to the wheel balancing device, the number of spokes is inputted manually into the wheel balancing device, and the wheel is rotated manually in such a manner, that the spokes of the wheel are situated in order at a predefined reference position. This operation is time-consuming and laborious.
A wheel balancing device of the present invention, which is intended, in particular, for balancing spoked wheels, includes a rotatable holding device that is configured to receive and rotatably support a wheel to be balanced, as well as at least one spoke sensor that is configured to detect the spokes of the wheel, in particular, their number and/or their positions.
A method of the present invention for determining the number and/or the positions of the spokes of a spoked wheel in a wheel balancing device includes the steps:
a) rotating the spoked wheel about its axis; and
b) detecting the spokes of the wheel, using a spoke sensor, while the wheel is rotated.
The present invention allows the number and the position of the spokes of a spoked wheel to be determined prior to and/or during the balancing operation in a rapid and convenient manner. The previously necessary positioning of the spokes at a predefined reference position by rotation of the wheel may be eliminated. As a result, the balancing of spoked wheels is markedly simplified and expedited.
The spoke sensor may be, in particular, a contactless sensor that is configured to detect the spokes in a non-contact manner. In this manner, damage to and/or aesthetic deterioration of the spokes by the sensor, as may occur in the case of a mechanical spoke sensor, are reliably prevented.
The spoke sensor may be an acoustic sensor, in particular, an ultrasonic sensor, or an optical sensor, in particular, a light reflection sensor. An optical sensor, which may take the form of, in particular, an infrared and/or laser sensor, also allows the spokes to be detected reliably at high rotational speeds.
In one specific embodiment, the wheel balancing device includes, in addition to the spoke sensor, an angular position sensor and an evaluation unit. The angular position sensor is configured to measure the current angular position of the wheel, and the evaluation unit is configured to determine the (angular) positions of the spokes along the circumference of the wheel. In this manner, the (angular) positions of the spokes in the circumferential direction of the wheel may be clearly determined. Through this, while determining the positions of the balancing weights, the (angular) positions of the spokes may be taken into account in such a manner, that the balancing weights are attached exclusively behind the spokes of the wheel, where they are not visible from the outside and are protected from external mechanical effects.
The evaluation unit may be configured to determine the positions of the spokes, while the wheel rotates about its axis, e.g., during the balancing operation, at a constant rotational speed, in particular, the balancing speed.
Alternatively, the evaluation unit may be configured to determine the positions of the spokes while the wheel is accelerated to the balancing speed or decelerated from the balancing speed.
Finally, the evaluation unit may be configured to determine the positions of the spokes while the wheel is rotated at a low speed, in particular, by hand, about its axis. A low rotational speed is particularly advantageous, when a sensor having a low rate of response, e.g., an acoustic sensor, is used as a spoke sensor.